KR101075013B1 - Rf vectormodulator for veamforming - Google Patents

Abstract

A beam shaping RF vector modulator is disclosed. According to an embodiment, the beamforming vector modulator includes a first amplifier configured to amplify an input single RF signal into a differential RF signal, and a two-stage polyphase filter configured to receive differential RF signals and output four signals having different phases. RF signal converting unit, and RF signal for synthesizing the output current of the variable gain amplifier and the variable gain amplifier for adjusting the amplitude and phase of the differential signal (I +, I-, Q +, Q-) via a transmission line load It includes a synthesis unit. By using a plurality of RF vector modulators according to the present invention, beam shaping in a 60Gbps next-generation WPAN can be easily implemented at low power.

Beamforming, vector modulator, WPAN, 60 GHz

Description

Beamforming RF Vector Modulators {RF VECTORMODULATOR FOR VEAMFORMING}

The present invention relates to a beam shaping RF vector modulator, and more particularly, to a beam shaping RF vector modulator capable of simply implementing low-power beamforming in a Gbps next-generation WPAN.

To provide directional wireless communication (i.e., increasing the signal strength by focusing the energy of the RF signal transmitted in a particular direction), the transceivers may apply a beamforming technique. Generally, beamforming techniques produce a focused antenna beam by shifting the signal in time or phase to provide a gain of the signal in the desired direction and to attenuate the signal in the other directions. It is a baseband processing technique for.

In addition, for this purpose, the receiver and the transmitter may be implemented as a system consisting of a plurality of antennas, a plurality of antennas, a plurality of transmitters and an array of receivers, and as shown in FIG. As a technique of maximizing a ratio, different phases are applied to a plurality of transceivers to adjust beams emitted from an antenna.

As a related art beam shaping technology, first, in Korean Patent Registration No. 10-0809313, there are a plurality of antennas and a plurality of RF receivers, and a method of improving wireless communication performance by selecting a receiver having the strongest power input to each receiver. It is about. In Korean Patent No. 10-0809313, a plurality of receivers are required, and there is a disadvantage in that there is no transmission / reception gain obtained through beamforming.

Second, Korean Patent No. 10-0465314 is a technique for implementing antenna beamforming using a digital beamforming method such as an isolated antenna, a multi-channel converter, a correlation vector estimator, and a beam shaper for a predetermined distance or more. Korean Patent No. 10-0465314 requires the same number of analog circuits as the number of antennas, and has low power consumption and signal processing speed to process high-speed data such as next-generation WPAN. Thus, applications in high speed and low power data communication systems are limited.

Third, Korean Patent Registration No. 10-0474849 is a technology to which the beamforming technique is applied to CDMA to improve communication performance. Disclosed is a method of shaping a beam in a desired direction as shown in FIG. 1 by adjusting a phase and an amplitude input to each antenna for beam shaping. The beam shaping method shown in FIG. 1 also requires a large number of transceivers and does not disclose specific designs for phase and amplitude generation.

In case of the second and third techniques, there is an advantage in that the communication performance is improved by using a plurality of transceivers by digitally forming beams to form beams in a desired direction.Because of this, the number of transceivers and resource consumption for signal processing are improved. There are various problems.

A wireless personal area network (WPAN) is a wireless network in which devices existing within a short distance perform data communication at low power. In the WPAN, data communication is performed using a time division multiple access (TDMA) scheme. Accordingly, devices to perform data communication monopolize a channel for a time allocated from a device called a Piconet Coordinator (CTAP) and perform data communication.

In 60 GHz communication, which is the next generation WPAN, as a Gbps-class wireless data communication system, conventional beamforming techniques as described above cannot be applied to the 60 GHz communication, which is the next generation WPAN. In addition, RF beam formers used for military use need to be replaced by commercial technologies in terms of size, power consumption and cost.

An object of the present invention is to provide an RF vector modulator for beam shaping that can easily implement the beam shaping in the next-generation WPAN Gbps class low power.

The object of the present invention is not limited to the above-mentioned object, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, a beamforming vector modulator includes: a first amplifier for amplifying an input single RF signal and outputting a differential RF signal having a different phase, and receiving a differential RF signal in phase; A variable gain amplifier including an RF signal converter for outputting four different signals, an I variable gain amplifier for amplifying the I signal, and a Q variable gain amplifier for amplifying the Q signal, and And an RF signal synthesizing unit for synthesizing the output current of the I variable gain amplifier and the output current of the Q variable gain amplifier via transmission line load.

The RF signal converter includes a polyphase filter that receives a differential RF signal and outputs I +, I-, Q +, and Q- signals, and the output stage of the polyphase filter has parasitic capacitances of an inductor and a circuit formed by using a transmission line. Resonant circuits constructed in parallel are connected to form a transmission line load.

The method may further include a variable gain amplifier controller including a VGA control DAC as controlling the amplification degree of the amplitude and phase of the I +, I−, Q +, and Q− signals.

The RF signal converter includes a two-stage polyphase filter and a transmission line load configured to connect an inductor using parasitic capacitance and a transmission line in parallel to an output terminal of the two-stage polyphase filter to form an inductor resonance circuit.

The I variable gain amplifier controls an input signal I + and I− by controlling a current source, a first phase selection signal for selecting a first phase, and a second phase selection signal for selecting a second phase in which there is a phase difference of 180 ° from the first phase. A phase selector for selecting a phase to be amplified with respect to the current source by the first phase select signal and a first amplifier and a second phase select signal for amplifying the input signal, and receive the current from the current source through the input signal I + And an I signal amplifier including a second amplifier for amplifying and outputting I−, wherein the voltage of the current source may be changed by a signal for varying a gain of the I variable gain amplifier.

The Q variable gain amplifier controls the input signals Q + and Q- by controlling a current source, a first phase selection signal for selecting a first phase, and a second phase selection signal for selecting a second phase in which there is a phase difference of 180 ° from the first phase. A phase selector for selecting a phase to be amplified with respect to the current source by the first phase selection signal and a first amplifier and a second phase selection signal for amplifying the input signal, and receiving the current from the current source through the input signal Q +. And a second amplifier amplifying and outputting Q-, wherein the voltage of the current source may be changed by a signal varying a gain of the Q variable gain amplifier.

The RF signal synthesizing unit synthesizes the output current of the I variable gain amplifier and the output current of the Q variable gain amplifier through the transmission line load in which the inductor using the parasitic capacitance and the transmission line are connected in parallel.

The transmission line may use an on-chip transmission line.

The beamforming vector modulator according to the present invention may further include a second amplifier for changing the differential output of the RF signal synthesizer into a single output.

Specific details of other embodiments are included in the detailed description and the drawings.

According to the present invention, a beam shaping can be realized simply and at low power by using a plurality of low noise amplifiers (LNAs), power amplifiers (PAs), and vector modulators without requiring a plurality of transceivers.

In addition, by implementing the beam shaping in a single input and output conditions, it is possible to configure an easier external interface.

In addition, by using an amplifier-based vector modulator, it is possible to design a lossless wideband beam former inside the chip, thereby miniaturizing and commercializing the beam forming system.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, only the embodiments are to make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims.

2 is a schematic block diagram of a beamforming vector modulator configuration according to an embodiment of the present invention. Referring to FIG. 2, the beamforming vector modulator 700 according to an embodiment may include an RF signal converter 200 including a first amplifier 100, a polyphase filter 210, and a transmission line load 220. A variable gain amplifier 300 including an I variable gain amplifier 310 and a Q variable gain amplifier 320 and an RF signal synthesizer 400 are included.

The first amplifier 100 amplifies the input RF single signal into a differential signal. For example, when a predetermined single RF signal having a phase of 0 ° is input, the signal is separated into an I signal having a phase of 0 ° and a Q signal having a phase of 180 °, and then converted into a differential RF signal and outputted.

The RF signal converter 200 receives an I signal and a Q signal, which are differential output signals of the first amplifier 100, converts the signal into four signals having different phases, and outputs the same. That is, I signal is converted into I + and I- signals, and Q signal is converted into Q + and Q- signals and output. Therefore, the RF signal converter 200 may also be referred to as a quadrature phase generator. The RF signal converter 200 may include a two-stage polyphase filter 210 and a transmission line load 220 connected to the output terminal of the filter. The output signal of the RF signal converter 200 outputs a signal having four phases different from the input I signal and the Q signal of I +, I−, Q +, and Q−.

The variable gain amplifier 300 receives the I + and I- signals output from the RF signal converter 220 and changes the amplitude and the polarity of the signals. It is included as a Q variable gain amplifier 320 for receiving the input to change the magnitude and phase (polarity) of the signal.

The RF signal synthesizing unit 400 sums the signals whose magnitudes and phases are converted through the variable gain amplifier 300. The vector modulator according to the present invention selects four phases of I / Q through the above-described RF signal converter 200 and inputs them to the variable gain amplifiers 310 and 320. The variable gain amplifier 300 adjusts the magnitude information of the I signal and the Q signal so that the I signal and the Q signal are combined in the RF signal synthesizer 400 to freely adjust the phase and magnitude of 360 °.

의 관계에 있다.In the formula, S ₀ is the result of summing the I signal and the Q signal in the RF signal synthesis unit 400, m ₁ is the magnitude of the I signal, m ₂ is the magnitude of the Q signal. m ₁ and m ₂

Is in a relationship.

The signal passing through the variable gain amplifiers 310 and 320 may be changed in phase by the RF signal synthesis unit 400 as shown in Equation 1, and the size of the signal may also be changed by changing the values of m ₁ and m ₂ . have.

On the other hand, the beam shaping vector modulator according to an embodiment of the present invention, the second amplifier unit 600 for converting the differential signal output from the RF signal synthesizer 400 to a single signal for use with an antenna using a single output, etc. ) May be further included. In addition, the variable gain amplifiers 310 and 320 may further include a variable gain amplifier controller 500 including a digital analog converter (DAC) for controlling amplification degree of a signal amplitude and phase.

3 illustrates a circuit configuration of an RF signal converter of the vector modulator shown in FIG. 2. Referring to FIG. 3, the RF signal converter 200 includes a polyphase filter 200 and a transmission line load 220.

The polyphase filter 210 has a bridge structure having four input terminals and four output terminals, of which two input terminals are grounded, and the other two input terminals input the I and Q signals, which are differential input signals. Receive. For example, an I signal may be input to the RF in + terminal illustrated in FIG. 2, and a Q signal may be input to the RF in− terminal. Polyphase filters can be connected in parallel and used in two stages to produce the output four phases of I / Q in a wide band for next-generation WPAN. I +, I-, Q + and Q- signals output from the output stage of the two-phase polyphase filter 210 can be transmitted without loss when the output stage is open, so as to minimize transmission loss. A transmission line load may be connected to the output terminal 220 of the polyphase filter to form a resonant circuit in which a parasitic capacitance 221 existing in a circuit and an inductor formed by using a transmission line are connected in parallel with each other. By configuring the transmission line load as the LC resonant circuit in this manner, the output node of the polyphase filter is virtually opened when the resonant circuit is resonated at a predetermined operating frequency. The transmission line load of the LC resonant circuit is connected to each output node of the polyphase filter.

In this way, the two-stage polyphase filter 210 and its output stage can be implemented with the transmission line load to implement the wideband characteristics of the WPAN.At the same time, the disadvantage of the polyphase filter can overcome the high loss by utilizing the on-chip transmission line. .

FIG. 4 is a circuit diagram illustrating a variable gain amplifier (I VGA) 310 of the variable gain amplifier according to an embodiment of the vector modulator shown in FIG. 2. Referring to FIG. 4, the I variable gain amplifier 310 according to an embodiment includes a current source 313 for supplying power, a phase selector 311, and an I signal amplifier 312 for amplifying a selected phase signal. .

The phase selector 311 selects phases amplified with respect to the input signals (eg, I + and I−) by the predetermined phase selection signals 420 and 430. A first phase selection signal (eg, Ic 420) for selecting a first phase and a second phase selection signal (eg, Icb 430) for selecting a second phase in which there is a 180 ° phase difference from the first phase. Only a phase selected from the input signal is amplified according to whether or not)) is on or off. For example, referring to FIG. 3, the phase selection signal Icon signal 314 changes the voltage of the current source 313 to change the gain of the I variable gain amplifier 310. The Ic signal 420 and the Icb signal 430 are phase selector signals. When the Ic signal 420 is On and the Icb signal 430 is Off, the current of the current source 313 is passed through M1 to the first amplifier M3, Flow to M4 312_a. The outputs of M3 and M4 312_a are connected to Iout + and Iout− terminals as shown in FIG. 3.

When the Ic signal 420 is Off and the Icb signal 430 is On, the current of the current source 313 is input to M5 and M6 312_b through M2. The output signal having the opposite polarity is amplified when the Ic signal 420 is turned on. As a result, by adjusting the Icon signal 410, Ic signal 420, and Icb signal 430, it is possible to appropriately amplify the phase and magnitude of the differential I +, I- signal input. The signal output to the Iout + and Iout− terminals is a signal whose magnitude and phase are amplified by the I variable gain amplifier 310. 4 illustrates a configuration circuit of the I variable gain amplifier (I VGA) 310, and the Q variable gain amplifier (Q VGA) 320 may also be configured in the same manner as shown in FIG. 4.

FIG. 5 is a circuit diagram illustrating an RF signal synthesizer according to an embodiment of the vector modulator shown in FIG. 2. The output signals I + 221, I- 222, Q + 223, and Q- 224 of the RF signal converter 200 are input to the I variable gain amplifier 310 and the Q variable gain amplifier 320, respectively. And amplified. The RF signal synthesizer 400 synthesizes the output signals i _{I +} 530 and i _{Q +} 540. The output signal i _{I +} 530 is an output signal of the I variable gain amplifier 310 with respect to the input signal I +, and i _{Q +} 540 is an output signal of the Q variable gain amplifier 320 with respect to the input signal Q +. The RF signal synthesis is performed through a transmission line load 510 configured by connecting a transmission line 511 and a parasitic capacitor 512 in parallel. Similarly, for the input signal I-221 and the input signal Q-224, i _I- and i _Q- are synthesized as i _out- via the transmission line load 520. That is, the outputs of the I variable gain amplifier 310 and the Q variable gain amplifier 320 are combined with the transmission line load in the form of current to synthesize the RF signal.

Those skilled in the art will appreciate that the present invention can be embodied in other specific forms without changing the technical spirit or essential features of the present invention. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the scope of the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present invention. Should be interpreted.

1 is a view showing a beam forming technique according to the prior art.

2 is a schematic block diagram of a beamforming RF vector modulator configuration according to an embodiment of the present invention.

3 illustrates a circuit configuration of an RF signal converter of the vector modulator shown in FIG. 2.

FIG. 4 is a block diagram illustrating an I variable gain amplifier circuit in a variable gain amplifier according to an embodiment of the vector modulator shown in FIG. 2.

FIG. 5 is a circuit diagram illustrating an RF signal synthesizer according to an embodiment of the vector modulator shown in FIG. 2.

`` Explanation of symbols for main parts of drawings ''

100: first amplifier 200: RF signal conversion unit

210: polyphase filter 220: transmission line load

221,511: transmission line 222,512: parasitic capacitor

300: variable gain amplifier 310: I variable gain amplifier

320: Q variable gain amplifier 400: RF signal synthesis unit

500: variable gain amplifier control unit 600: second amplifier unit

Claims (8)

A first amplifier for amplifying the input single RF signal and outputting a differential RF signal having a different phase; Receives the differential RF signal and outputs four differential I +, I-, Q + and Q- signals having different phases, and a polyphase filter having a bridge structure having four input terminals and four output terminals connected in parallel. Only polyphase filter; And a transmission line load having a transmission line load connected to an inductor using a parasitic capacitance and a transmission line in parallel to form an inductor resonance circuit, connected to an output terminal of the two-stage polyphase filter. I variable gain amplifier (VGA) for varying the amplitude and phase of the differential I + and I- signals according to a predetermined control signal and a Q variable gain amplifier for varying the amplitude and phase of the differential Q + and Q- signals. A variable gain amplifier comprising a; And RF signal synthesizing unit for synthesizing the output current of the I variable gain amplifier and the output current of the Q variable gain amplifier RF vector modulator for beam forming comprising a. The method of claim 1, Variable gain amplifier control unit including a VGA control digital analog converter (DAC) for controlling the amplitude of the amplitude and phase of the differential I +, I-, Q + and Q-signals that are output signals of the RF signal converter RF vector modulator for beam shaping further comprising. delete The method of claim 1, wherein the I variable gain amplifier Current source; A phase amplified with respect to the input signals I + and I- is controlled by controlling a first phase selection signal for selecting a first phase and a second phase selection signal for selecting a second phase having a phase difference of 180 ° with the first phase. A phase selector for selecting; And The input signal I + and I- may be received by receiving the current of the current source by the first amplifier and the second phase selection signal which receives the current of the current source by the first phase selection signal and amplifies the output signal. Including an I signal amplifier including a second amplifier for amplifying and outputting, And the voltage of the current source is changed by a signal varying the gain of the I variable gain amplifier. The method of claim 1, wherein the Q variable gain amplifier Current source; A phase amplified with respect to the input signals Q + and Q- is controlled by controlling a first phase selection signal for selecting a first phase and a second phase selection signal for selecting a second phase having a phase difference of 180 ° with the first phase. A phase selector for selecting; And The current signal of the current source is input by the first amplifier and the second phase selection signal which receives the current of the current source by the first phase selection signal and amplifies the output signal and outputs the input signals Q + and Q-. It includes a Q signal amplifier including a second amplifier for amplifying and outputting, And the voltage of the current source is changed by a signal varying the gain of the Q variable gain amplifier. The method of claim 1, wherein the RF signal synthesis unit And an output current of the I variable gain amplifier and an output current of the Q variable gain amplifier through a transmission line load in which a parasitic capacitance and an inductor using a transmission line are connected in parallel. The method of claim 1, wherein the transmission line Beamforming RF vector modulator using On-Chip Transmission Line. The method of claim 1, And a second amplifier configured to change the differential output of the RF signal synthesizer into a single output.

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